NEW YORK  (CBSNewYork) — A new report from the Centers for Disease Control shows there’s a new, sick side to summer swimming.

Before you dive into the pool, CBS2’s Kristine Johnson explains what you need to know about “what’s in the water.”

No matter what your parents may tell you — there’s no magic chemical that reveals the presence of urine in a swimming pool.

Chlorine does help keep a pool clean, but it doesn’t get everything.

“Chlorine is eliminating most contaminants and bacteria but it doesn’t guarantee that everything is removed,” Dr. Jake Deutsch, Emergency Medicine Specialist, explained.

Even if you notice a strong smell of chlorine at your local pool, that’s not actually a sign the pool is extra clean.

According to the Centers for Disease Control, the stronger the chlorine smell — the more pee is in the pool.

If your eyes turn very red after swimming, that’s also a sign the chlorine couldn’t fight all the urine, sweat and whatever else swimmers brought into the water with them.

“When we go into a swimming pool, we’re actually putting our face where a lot of people have put their rear-end,” Epidemiologist Dr. Melvin Kramer said.

The CDC found that 58 percent of pool samples tested positive for E. coli, a bacteria normally found in feces, which can make us quite sick, says Kramer.

“When we’re swimming, we consume water through our mouth — our nose — our eyes,” Kramer said.

Experts say pool water can also carry Legionella, a bacteria that can cause pneumonia, as well as gastro-intestinal diseases, like the norovirus.

“Look, we don’t live in a bubble,” Kramer said. “I go swimming all the time.”

Kramer says you just need to know how to limit your risk.

The CDC says the best thing you can do is to shower with soap before and after you swim.

“Ask around, moms know what’s going on, as well as any health official, and if somebody’s kid has gotten sick you want to make sure that you’re aware of that protecting and your family as well,” Deutsch adds.

The same concerns hold true for hot tubs and water parks.